<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<input id="one">+<input id="two"><span id="eq">=</span> <span id="v"> </span>
<SCRIPT>
    var  oneInput =document.getElementById('one');
    var twoInput=document.getElementById('two');
    var eq=document.getElementById('eq');
    var v=document.getElementById('v')
    eq.onclick=function () {
        var one =oneInput.value
        var two=twoInput.value
        v.innerText=(parseFloat(one)+parseFloat(two))
    }
</SCRIPT>
</body>
</html>